1. Field of the Invention
The present invention relates to a Plasma Display Panel (PDP), and more particularly, to a PDP that forms an image by applying a discharge voltage to a plurality of electrodes arranged on two panels facing each other to generate ultraviolet rays which excite phosphor layers.
2. Description of the Related Art
Recently, a flat panel display employing a plasma display panel (PDP) has been in the spotlight as a next generation display owing to superior characteristics such as a large-sized screen, a high picture quality, a slim profile and a wide viewing angle, a simple fabrication method, and it being easy to make a large-sized screen compared with other flat displays.
The PDP may be classified into a DC (direct current) type PDP, an AC (alternating current) type PDP, and a hybrid type PDP according to a discharge voltage applied to the panel, and also be classified into a facing discharge type PDP and a surface discharge type PDP according to a discharge structure.
The DC type PDP has a structure in which all electrodes are exposed to a discharge space and charges move directly between the electrodes. The AC type PDP has a structure in which at least one electrode is covered with a dielectric layer, and charges do not move directly between the corresponding electrodes but discharge is performed by wall charges.
The DC type PDP has a drawback in that the electrodes are seriously damaged because charges are directly moved between corresponding electrodes. To this end, the AC type PDP, especially, an AC type PDP having a three-electrode surface discharge structure has been generally employed.
Referring to FIG. 1, a conventional surface discharge type PDP 10 with such an AC type three-electrode surface discharge structure includes a front panel 20 and a rear panel 30.
Address electrodes 33 generating an address discharge, a rear dielectric layer 35 covering the address electrodes 33, barrier ribs 37 partitioning discharge cells, and a phosphor layer 39 formed on both sidewalls of each of the barrier ribs 37 and on the rear dielectric layer 35 on which the barrier ribs 37 are not formed are arranged on the rear panel 30.
The front panel 20 is spaced apart from and facing the rear panel 30. Moreover, common electrodes 22, scan electrodes 23, a front dielectric layer 25 covering the common electrodes 22 and the scan electrodes 23, and a passivation layer 29 covering the front dielectric layer 25 are arranged on the front panel.
The common electrodes 22 disposed on the front panel 20 through which visible rays generated from the phosphor layer 39 of a discharge space pass, have a transparent common electrode 22a and a bus common electrode 22b disposed at one edge of the transparent common electrode 22a, the scan electrodes 23 have a transparent scan electrode 23a and a bus scan electrode 23b disposed at one edge of the transparent scan electrode 23a, and the front dielectric layer 25 and the passivation layer 29 covering the front dielectric layer 25 are sequentially formed on the common electrodes 22 and the scan electrodes 23. Due to the aforementioned elements, only 60% of the visible rays can pass through the front panel 20, which serves as an important factor.
Also, the conventional surface discharge PDP 10 has a drawback that the luminous efficiency is low because electrodes generating a discharge are arranged on an upper surface of the discharge space, i.e., on an inner surface of the front panel 20 through which the visible rays pass so that the discharge is generated in the inner surface of the front panel 20.
Further, the conventional surface discharge PDP 10 may cause a permanent residual image because when the conventional surface discharge PDP 10 is used for a long time, charged particles of discharge gases generate ion sputtering in the phosphor due to an applied electric field.
Furthermore, the front dielectric layer formed on the front panel 20 should be transparent, such that the visible rays excited from the phosphor layer pass therethrough. Due to the transparent front dielectric layer, external light that is incident into the PDP is reflected by the transparent front dielectric layer and then emitted to an exterior. As a result, the conventional surface discharge PDP 10 has a drawback that a contrast ratio is not high.
To improve the above drawbacks, a black stripe is disposed on non-discharge regions, or a line width of the bus electrode is increased, thereby more or less increasing the contrast ratio. However, since the size of the non-discharge area is limited so as to maintain the aperture ratio above a predetermined value, there is a limitation in disposing the black stripe or increasing the line width of the bus electrode.